43. Skin Appendages Exocrine glands Nails Sebaceous glands Sweat glands Merocrine glands Apocrine glands Heat regulating Stress stimulated which include are either which are Hair which are Produce oil Empty into hair follicle Open to skin surface
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55. Pigment distribution in hair Human Caucasian hair Human red hair Human Mongoloid hair Dog hair
56.
57.
58.
59. Skin Appendages 87 88 89 90 92 93 91 94 95 which include are either which are 86 which are
The epidermis layer is the stratified squamous layer. The dermis is dense connective tissue. The hypodermis is not technically part of the skin, but anchors it to underlying organs.
Name the body cavities open to the exterior: Respiratory, digestive, urinary
Which body cavities are closed to the exterior? Thoracic, abdominopelvic.
Get picture of peritoneum. Check Marieb site for interactives.
So what kind of membrane is this? Cutaneous
.5 to 4mm thick Dermis and epidermis are firmly attached to each other. Divided by wavy (undulating) borderline. A blister occurs when dermis separates from the epidermis. Callus is a gross thickening of the epidermis. Hypodermis is not technically part of the skin.
5 layers in thick skin like palms and soles of feet. 4 layers elsewhere Basale: Usually made up of columnar cells. Mostly keratinocytes, 25% melanocytes and some Merkel’s cells (touch receptors). Melanocytes have projections (fingers) that touch all keratinocytes. Keratinocytes then phagocytize ends of melaninocyte “fingers” and get melanin. Melanin then coats the “sunny” side of the keratinocytes, protecting them from UV damage to DNA. Click to next slide for illustration. Stratum Spinosum- spiny layer. Mitotic cells pushed upward from stratum basale. Stratum granulosum: production of keratin begins as cells enter this layer. Stratum lucidum: Clear, flat layer full of keratin. Found only in the palms of hands and soles of feet. Stratum Corneum: 20-30 layers thick: ¾ of epidermal thickness. Shingle-like, dead cells full of keratin. Rubs and flakes off every 25-45 days. Friction causes the stratum corneum to add even more layers forming a callus or, over a bone projection, called a corn.
Change answer at school.
Connective tissue with a gel-like matrix of collagen and elastic fibers. Cells are fibroblasts, macrophages, mast cells, WBCs. Loss of collagen and elastin fibers are products of ageing.
Between fibers are less dense regions called lines of cleavage or tension lines. Usually run longitudinally on limbs and circularly in neck and trunk. Surgeons try to cut with lines of cleavage so incisions gape less, heal more quickly. Flexure lines (dermal folds) result from dermis being secured to deeper structures by hypodermis. Wrists, palms, solds of feet, fingers and toes. When skin cannot slide to accommodate bending of joint, thus folds are needed.
Another note on melanin. Though melanin offers protection, too much sun exposure causes clumping of elastin fibers leading to leathery skin (solar elastosis).
Another note on melanin. Though melanin offers protection, too much sun exposure causes clumping of elastin fibers leading to leathery skin (solar elsastosis) Also too much UV can depress immune system (cold sores outbreak) as well as alter DNA. Melanin: color can range from yellow to orange to brown. Carotene: orange-yellow pigment. More prominent in Asians. Adipose also looks yellow. Prominent in palms and soles. Hemoglobin: responsible for pinkish color in caucasians.
Add picture of bruise, cyanosis, or jaundice
Go over and describe different structures. Point out that sweat glands go directly to surface. Sebaceous gland empties into hair follicle. Show how epidermis wraps around hair follicle. Show arrector pili muscle, nerve, artery, vein. Point out nerve endings—pacinian corpuscle or merkels. Note page 103 after bold word “hair follicle” that the follicle is an extension of epidermis deep into dermis and that it plays a part in tissue repair. If surface epidermis is damaged in burn or otherwise the epidermal cells can divide and serve as a source of new epithelial cells in the region.
Exocrine—what other kind of glands have you heard of? Endocrine. What do the terms tell you about where the two types of glands might secrete their products?
Small on body trunk and limbs, but large on face, neck and upper chest. Central cells accumulate triglycerides, cholesterol and other lipids, become engorged then fragment. Ducted into hair follicle. Also impedes water loss from skin.
2.5 million on body
Minor protection functions: guarding head from trauma, heat loss and sunlight. Eyelashes shield eyes. Nasal hair keeps dust out of respiratory tract. Hair made of fused, keratinized cells. 100,000 hairs in scalp. 30,000 hairs in man’s beard. Velus hair: pale, fine hair on womens’ and children’s bodies. Terminal hair-coarser, darker hair on head, eyebrows.
Medulla large cells partially separated by air spaces. Cortex several layers of flattened cells Cuticle single layer of overlapping cells. Overlap from below like shingles on a roof. Split ends: abrasion of cuticle causes cuticle to wear away at tip allowing keratin fibrils in cortex and medulla to frizz out.
Top to bottom: Caucasian, Negroid, Mongoloid
Get picture of hair follicle
Exocrine—what other kind of glands have you heard of? Endocrine. What do the terms tell you about where the two types of glands might secrete their products?
Hoof or claw in animals, non-living Nail folds: borders of nail include cuticle. Nail bed: epithelial cells underlaying nail. Thickened portion at proximal end of nail is the matrix from which the cells arise. Nail is keratinzed cells that move forward as new cells are made at the matrix. Pink in nail is from blood supply in dermis Lanula: this is the area where the stratum basale (germinativum) cells are dividing.
Chemicals can be acids or bases. All of these denature cell proteins (enzymes and others) and cause cell death. Burned skin is sterile for 24 hours then bacteria, fungi & viruses can invade since the mechanical barrier is damaged. These pathogens grow quickly in the rich environment of dead tissue. Metabolism is affected: burn patients need 1000s of extra calories to repair tissue. They can’t eat enough, so they get IV feedings.
Regeneration occurs because epithelial cells are still present.
Coppertone ad has changed. Baby has no tan or burn.
![Body Membrane Types ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)